Trapeliopsis aeneofusca
Trapeliopsis aeneofusca is a rare morph of T. gelatinosa that lacks any green epithecial pigment, as suspected by Purvis & Smith (2009) and confirmed using molecular methods by Resl et al. (2015).

Purvis, O.W. & Smith, C.W. (2009). Trapeliopsis. In Lichens of Great Britain and Ireland (Smith, C.W., Aptroot, A., Coppins, B.J., Fletcher, A., Gilbert, O.L., James, P.W. & Wolseley, P.A. eds): 908–910. London: British Lichen Society.
Resl, P., Schneider, K., Westberg, M., Printzen, C., Palice, Z., Thor, G., Fryday, A., Mayrhofer, H. & Spribille, T. (2015). Diagnostics for a troubled backbone: testing topological hypotheses of trapelioid lichenized fungi in a large-scale phylogeny of Ostropomycetidae (Lecanoromycetes). Fungal Diversity 73: 239–258.